It sounds like there's something about the formatting of the ISDN setup message that isn't quite standard and all carriers other than AT&T are fixing it up at the terminating end. What does an AT&T cell phone display instead of the CLID?

Perhaps it's the format of the outgoing number that makes a difference.

Debug isdn l2-formatted and look at the calling party number on the outbound message.

Try it as NPA-NXX-XXXX, 1-NPA-NXX-XXXX and e.164 +1-NPA-NXX-XXXX

Also look at the outgoing ISDN call rype, national vs. local vs. unknown.

Lastly, make sure that your switch type matches the carrier's. These days most are NI-2.

We also have had these symptoms but just for AT&T Iphone 6 phones. (google it) For us, it was really a bad ANI issue that causes no CNAM database dip on the far end.

We were sending ANI from a digital Panasonic PBX over a classic NI-2 PRI to a Lucent 5E switch. You can get more vanilla than that. Our carrier "broke" the outbound CNAM when they started to use "NeutralTandem.com" to transit the traffic to the AT&T network.

The bottom line was we the carrier asked us to change the ANI format an/or the numbering plan. I can't recall. THEN the carrier fixed it.

Thanks for the input guys. I've done a capture using "DEBUG ISDN L2-FORMATTED" and "DEBUG VOICE VERBOSE" for calls to VERIZON SUBSCRIBER (CALLER-ID OK) and ATT SUBSCRIBER (CALLER-ID NOT OK) below. Could you tell me if you see anything indicating bad ANI?

You are correct, I was running "debug isdn l2-messages" not "debug isdn l2-formatted".

However, I have an update...

After some extensive investigation (with the assistance of Patrick from Adtran support), I found that my IP-PBX, when hosting the PRI directly with the internal PRI interface, all caller-id to AT&T subscribers worked without issue. So, since my PBX (Allworx) is able to capture PRI messages (equivalent to "debug isdn l2-formatted"), we captured a call from the TA-908E gateway as well as the PBX, and compared the results.

The result that stood out was, the Allworx was sending caller-id in national format, and the AdTran was not (by default it sends caller-id in a different format, I'm not sure what that is, can someone help with this? In the debug it just shows up as number type: unknown). Patrick from AdTran support suggested that we setup an ANI map to have caller-id sent in national format when the pattern matched. We matched for ANY 10 digit number with the following command:

isdn-number-template 0 prefix "" national NXXNXXXXXX

Once we set this up, caller-id to AT&T finally worked! More importantly, it continued to work on all of the other carriers that did NOT have an issue as well. So, THANK YOU PATRICK FROM ADTRAN SUPPORT, you da man! I've been trying to get this resolved for quite a while, and AdTran and the PBX vendor all insisted that it was the carrier (AT&T or the PRI provider) and not the PBX or gateway because it worked on most other carriers. Does that make this an AT&T issue? Perhaps, I'd say PROBABLY...but knowing this and spreading it here on the forums will hopefully make this an issue that does not affect people anymore.

Joseph, I went ahead and flagged this post as "Assumed Answered". If any of the responses on this thread assisted you, please mark them as Correct or Helpful as the case may be with the applicable buttons. This will make them visible and help other members of the community find solutions more easily. If you still need assistance, we would be more than happy to continue working with you on this - just let us know in a reply.